Which do you think is the most important of Aristotle’s artistic proofs? Explain your answer.

Michael Burke says:

[A]rtistic proofs are arguments or proofs that need skill and effort in order to be brought into being. Non-artistic proofs are arguments or proofs that need no skill or real effort to be created; rather, they simply need to be recognised--taken off the shelf, as it were--and employed by a writer or speaker.

In Aristotle's rhetorical theory, the artistic proofs are ethos (ethical proof), pathos (emotional proof), and logos (logical proof).

Explanation:

Aristotle on Inartistic and Artistic Proofs

Aristotle

Of the modes of persuasion some belong strictly to the art of rhetoric and some do not. By the latter [i.e., inartistic proofs] I mean such things as are not supplied by the speaker but are there at the outset--witnesses, evidence given under torture, written contracts, and so on. By the former [i.e., artistic proofs] I mean such as we can ourselves construct by means of the principles of rhetoric. The one kind has merely to be used, the other has to be invented.

Of the modes of persuasion furnished by the spoken word there are three kinds. The first kind depends on the personal character of the speaker [ethos]; the second on putting the audience into a certain frame of mind [pathos]; the third on the proof, or apparent proof, provided by the words of the speech itself [logos]